1. Field of the invention
The present invention relates to a deflection yoke, in particular, which can reduce power consumption while elevating deflection sensitivity.
2. Description of the Prior Art
In general, a Cathode Ray Tube (CRT) in a television or a monitor has a deflection yoke for correctly deflecting RGB beams scanned from an electron gun to a fluorescent screen applied on a screen of the CRT. Such a deflection yoke functioning as one of the most important magnetic components in the CRT serves to deflect the electron beams from the electron gun so that electric signals transmitted in time sequence can be reproduced as images on the screen of the CRT.
In other words, since the electron beams project ed from the electron gun directly move onto the screen with a high voltage to light only central phosphors in the screen, the deflection yoke externally deflects the electron beams in the order of scanning. Here, the deflection yoke forms a magnetic field to deflect the electron beams correctly to the fluorescent screen applied on the screen of the CRT based upon the fact that the electrons are forced to change the course thereof while passing through the magnetic field.
FIG. 1 is a side elevation view for showing a general CRT. As shown in FIG. 1, a deflection yoke 4 is placed in an RGB electron gun section 3 of the CRT 1 to deflect electron beams scanned from an electron gun 3a toward a fluorescent screen applied on a screen surface 2.
Such a deflection yoke 4 comprises a coil separator 10 constituted of a pair of symmetric upper and lower parts which are coupled into one unit.
The coil separator 10 is provided to mutually insulate horizontal deflection coils 15 and vertical deflection coils 16 while assembling the same at suitable positions, and comprised of a screen portion 11a for being coupled to one side of a screen surface of the CRT 1, a rear cover 11b and a neck portion 12 integrally extended from a central surface of the rear cover 11b for being coupled to the electron gun section 3 of the CRT 1.
The coil separator 10 is respectively provided in the inner and outer peripheries with the horizontal deflection coils 15 and the vertical deflection coils 16 for forming horizontal magnetic deflection and vertical magnetic deflection via externally applied power.
Further, a pair of ferrite cores 14 made of a magnetic substance are installed to wrap the vertical deflection coils 16 to strengthen the vertical magnetic deflection generated from the vertical deflection coils 16.
The deflection yoke 4 configured like this is installed in the neck portion 12 of the CRT 1. When the horizontal deflection coils 15 and the vertical deflection coils 16 are applied with a sawtooth wave pulse, the deflection yoke 4 generates the magnetic field based on the Fleming""s left hand rule to deflect the RGB electron beams emitted from the electron gun 3a of the CRT so as to determine scanning positions on the screen.
In the above deflection yoke 4, the deflection coils and ferrite cores 14 as well as the coil separator 10 are designed according to the tube shape of the CRT 1.
As shown in FIG. 2, in other words, the conventional deflection yoke 100 is configured to have horizontal deflection coils 120 for forming a horizontal magnetic deflection and vertical deflection coils 130 for forming a vertical magnetic deflection, in which the horizontal deflection coils 120 are provided in the inner periphery and the vertical deflection coils 130 are provided in the outer periphery about the coil separator 110 so that the coils 120 and 130 form concentric circles.
The vertical deflection coils 130 are provided in the outer periphery with a ferrite core 140 for strengthening the vertical magnetic deflection from the vertical deflection coils 130 as above. The ferrite core 140 also has a circular sectional shape.
As shown in FIG. 3, the coil separator 110 is formed into the shape of a funnel in general, and comprised of a screen portion 111 having a large diameter, a neck portion 114 having a small diameter, a body 112 connecting between the screen portion 111 and the neck portion 114 and a rear cover 113 having the shape of boards at a position adjacent to the neck portion 114. The coil separator 110 mutually insulates the horizontal deflection coils 120 and the vertical deflection coils 130, as shown in FIG. 2, while maintains the same in suitable positions.
In the conventional deflection yoke 100, however, the CRT section to which the deflection yoke 100 is attached is manufactured into a circular shape due to difficulty in manufacture even though the screen surface of the CRT has a rectangular shape with an aspect ratio of 4:3 or 16:9 thereby resulting in problems that enhancement of deflection sensitivity is restricted and power consumption increases as well.
As CRTs of TVs or monitors are flattened or large sized recently, the CRTs require those deflection yokes which can guarantee high deflection sensitivity. However, since the deflection yokes have circular cross sections, there are limitations in increasing deflection efficiencies according to traces of the electron beams.
In order to solve the above problems, a ferrite core having a quadrangular cross section was proposed in the prior art. However, the following problems are incurred in forming the ferrite core into the quadrangular shape.
In general, since the ferrite core is formed through compression molding, it has a very poor workability. Also, the ferrite core requires a precise working process thereby lowering the productivity and increasing the manufacturing cost by a large margin.
In other words, the ferrite core having the cross section manufactured into the angled shape has an ununiform contraction dispersion which is generated by a large amount in a plastic deformation process over the ferrite core having the circular cross section. This accompanies a working process for improving the dispersion, thereby increasing the number of process steps and lowering the yield.
Accordingly, the present invention has been made to solve the above problems and it is an object of the present invention to provide a deflection yoke which comprises a coil separator and horizontal deflection coils having angular cross sectional shapes and a ferrite core and vertical deflection coils having circular cross sectional shapes to improve deflection sensitivity thereby reducing power consumption.
It is another object of the invention to provide a deflection yoke which comprises support structures in an outer periphery of a coil separator at the same interval for supporting horizontal deflection coils with an angular cross section, vertical deflection coils with a circular cross section and a ferrite core so as to improve deflection sensitivity as well as enhance mass productivity.
According to an aspect of the invention, it is provided a deflection yoke comprising: a coil separator formed into the shape of a quadrangular pyramid with a quadrangular cross section, and comprising a screen portion coupled to a screen of a CRT and a neck portion integrally extended from said screen portion and coupled to an electron gun section of the CRT; horizontal and vertical deflection coils provided in inner and outer peripheries of said coil separator for forming magnetic deflections to deflect electron beams in horizontal and vertical directions; and a ferrite core provided in the outside of said coil separator and having a substantially conical shape for strengthening the magnetic deflections.
The deflection yoke is further characterized in that said vertical deflection coils closely contact to an outer surface of said coil separator.
The deflection yoke is characterized in that said vertical deflection coils closely contact to an inner surface of said ferrite core.
The deflection yoke is further characterized in that said horizontal deflection coils are angularly wound to closely contact to an inner surface of said coil separator, and said vertical deflection coils are circularly wound to closely contact to an inner surface of said ferrite core.
The deflection yoke is still characterized in that said horizontal deflection coils have a rectangular cross sectional shape with an aspect ratio of 4:3 or 16:9.
According to another aspect of the invention, it is provided a deflection yoke comprising: a coil separator comprising a screen portion coupled to one side of a screen surface of a CRT, a neck portion coupled to an electron gun section of the CRT, and a body having the shape of a quadrangular pyramid with a quadrangular cross section for connecting said screen portion and said neck portion; horizontal and vertical deflection coils provided in inner and outer peripheries of said coil separator for forming magnetic deflections to deflect electron beams in horizontal and vertical directions; a ferrite core provided in an outer surface of said coil separator and made of a magnetic substance for strengthening the magnetic deflections; and at least one support rib integrally projected along an outer surface of said coil separator for uniformly supporting an inner surface of said ferrite core.
The deflection yoke is characterized in that said support rib is provided at positions in an outer periphery of said body adjacent to said screen portion and said neck portion, and has a curvature for uniformly contacting to upper and lower inner peripheries of said ferrite core having the circular cross section.
The deflection yoke is further characterized in that said vertical deflection coils are angularly shaped for closely contacting to an outer surface of said coil separator.
The deflection yoke is characterized in that said vertical deflection coils uniformly contact to an inner surface of said ferrite core.
The deflection yoke is further characterized in that said horizontal deflection coils are angularly wound for closely contacting to an inner surface of said coil separator, and said vertical deflection coils are circularly wound for closely contacting to an inner surface of said ferrite core.
The deflection yoke is further characterized in that said coil separator comprises: symmetric right and left parts joining into one unit; and insulation ribs integrally projected from interfaces of said right and left parts for mutually insulating right and left parts of said vertical deflection coils.
The deflection yoke is still characterized in that said horizontal deflection coils have a rectangular cross sectional shape with an aspect ratio of 4:3 or 16:9.